Efficacy of different Plant essential oils against Penicillium expansum causing fruit rot of grapes

Penicillium rot (PR) caused by Penicillium expansum is a severe fruit rot of grapes in Pakistan, causing serious threat for the environment and responsible to market losses. The objective of this study is to find out some effective plant essential oils as an alternative to synthetic fungicides against P. expansum causing fruit rot of grapes. For this purpose, three selected plant essential oils (EOs) viz. Olive (EO), Citrus peel (EO) and Fenugreek (EO) at 400, 600 and 800 ppm concentrations were studied by using different methods under in vitro condition as well as application on grapes against previously isolated culture of P. expansum designated as (Isolate ID. APE10TL3) on grapes bunches respectively. Results showed that Citrus peel (EO) at all concentrations showed significant result to control the mycelial growth (89.3, 94 and 97.5%) in contact assay method as well as 90.1, 96.3 and 99% growth inhibition regarding fungal culture transfer (FCT) experiment while, in case of well diffusion method 41%, 46% and 52% growth inhibition was recorded at 7 day of incubation followed by olive (EO) and fenugreek (EO) as compared to control 0% growth inhibition was measured. Moreover, the Citrus peel (EO) was further evaluated for the presence of anti-fungal compounds viz. terpene, alkaloids, phenolic and saponins employing standard protocols and found positive for the presence of all compounds. During the application of citrus peel essential oil at (800 ppm) concentration on fruit bunches for the determination of decaying percentage. The result showed 12.53% decay caused by P. expansum on treated bunches up to six days of storage and control was 85.14% calculated. Keeping in all view, Citrus peel (EO) possessing good inhibitory action upon Penicillium expensum might be used as a potential candidate for preservation and extension of shelf-life of grapes commercially.